1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) apparatus and its driving method, and more particularly, to a field sequential driving type full-color LCD apparatus and its driving method.
2. Description of the Related Art
Field sequential driving type LCD apparatuses have been developed where three color signals, i.e., a red signal, a green signal and a blue signal are time-divisionally displayed. In such field sequential driving type LCD apparatuses, since three color filters are unnecessary and pixels are in common for the red signal, the green signal and the blue signal, a higher numerical aperture can be realized, so that the utilization of optical sources is higher which would further decrease the power consumption. Therefore, field sequential driving type LCD apparatuses have been used in mobile apparatuses such as mobile telephones or personal digital assistants (PDAs).
In a prior art field sequential driving type LCD apparatus, a black signal is written into all the pixels before a color signal for one sub-frame is written into the pixels. Then, rows of the pixels are sequentially selected so that video signal levels are written thereinto. Finally, when the change of the transmittivities of the rows of the pixels is very small, a respective backlight is turned ON for a predetermined time period. This will be explained later in detail.
In the above-described prior art field sequential driving type LCD apparatus, however, in order to increase the brightness, if the predetermined time period where the back light is being turned ON is increased, large differences are generated among the transmittivities of the rows, so that the brightness is irregular.